I got curious about the details, and, turns out, it is related to whether the short scale or long scale system is used.[0]
Short scale is the traditional million-billion-trillion-etc. Long scale is million-milliard-billion-billiard-etc. It isn't just naming for the same thing, as billion would actually have different power across those systems (power of 9 vs power of 12).
Looks like both russia and france got their own variations of it. Russia uses short scale, but swapped the name for billion to milliard. While francophone, scandinavian, and a few other countries tend to use long scale.
But for a number such as '3 milliarder', one often writes '3.000 millioner' instead. Exactly why I don't know, but I would guess it has something to do with more accurately reflecting the size of the number. It might not be as clear that the number is 1000x the size with a simple change in the end of the word. The difference between a million and a billion is about a billion, after all.
Speaking of confusion about numbers, just wait until you see how different countries divide up large numbers. Some countries, such as Norway write one million as 1.000.000,00 while others write it as 1,000,000.00.
There might be other languages where this occur as well, not just Russian and Indonesian.
https://simple.wikipedia.org/wiki/Long_and_short_scales
The long system makes vastly more sense, but in the English world we use the short system, except of course for the English themselves who used to use the long system and tragically regressed to the short system officially in the 1970's.
Of course, in my perfect world, we would use neither because we'd be using base-12: https://en.wikipedia.org/wiki/Duodecimal
I think incrementing by a 1000 is vastly more simple than 1000 or million. It doubles the amount of names which may be useful scientifically but in a layman's world, we don't really use things past a billion.
$1k, $1M, $1B, $1T, $1Q seem like pretty quick and easy abbreviations for all amounts of money that are commonly dealt with, at least for US or European currencies.
Short scale: A short n-illion equals 10^(3n + 3)
Long scale: A long n-illion equals 10^(6n) and a long n-illiard equals 10^(6n+3)
Why can't they just use plain English nobody knows. \s
But it gets more interesting, they use the same words (or a very similar one) as in English to express different concepts.
"Crier" sounds like cry, but it means "to scream".